This project is concerned with investigating the mechanisms responsible for the genesis of myopia and eye enlargement that are caused by neonatal lid fusion in macaque monkeys. The various components of the refractive state will be measured. Experiments are designed to analyze the effects of (a) light, (b) form deprivation, (c) accomodation, (d) mechanical pressure on the globe, (e) intraocular pressure and (f) temperature on the myopia and eye elongation caused by neonatal lid fusion. The objective is to explore the usefulness of the myopia caused by lid closure as an animal model for the development of myopia in humans.